NBC Poll: Romney, Paul Neck and Neck

Former Massachusetts Gov. Mitt Romney and Texas Rep. Ron Paul are pretty much even-steven in the closing days of tough campaigning for the Iowa caucuses Tuesday, according to a new NBC-Marist Poll.

Romney has 23 percent support among likely caucus voters, compared with 21 percent for Paul, according to the poll. That’s well within the poll’s 4.8 percentage point (plus or minus) margin of error.

Former Pennsylvania Sen. Rick Santorum has rocketed to third place with 15 percent support, and Texas Gov. Rick Perry has risen to 14 percent. Former House Speaker Newt Gingrich has slipped to 13 percent, and Minnesota Rep. Michele Bachmann trails with 6 percent.

In the previous NBC-Marist poll, conducted in late November, Gingrich led with 28 percent support, followed by Romney and Paul tied with 19 percent, Perry with 10 percent, Bachmann with 7 percent, and Santorum with 6 percent.

The latest poll numbers are close to those generated in a CNN/Time survey released this week.

“More than half of [Gingrich’s] support has evaporated,” said Lee Miringoff, director of the Marist College Institute for Public Opinion, which conducted the survey. He said the millions of dollars spent by the pro-Romney super PAC and the Paul campaign on TV ads attacking Gingrich are responsible for the former House speaker’s decline.

Just 7 percent of likely caucus voters see Romney as the true conservative in the GOP field. But only 21 percent say he’s an unacceptable nominee. And conservative voters are split among several candidates, giving the former Massachusetts governor an advantage.